When it comes to conserving energy in your home, one of the best things you can do is identify and seal air leaks. In this article, building-science specialist John Straube outlines the various ways in which a house can leak conditioned air, wasting resources and ultimately your money. Wind pushes drafts through a leaky house, a definite problem in the cold winter months. The stack effect can be problematic in both summer and winter. In winter, rising warm air leaks through the roof and is replaced by cold air sucked in through the bottom floor. In summer, warm air is pulled in through the roof while cool conditioned air is forced out of lower floors. In a house, mechanicals also contribute. Devices such as gas fireplaces, dryers, furnaces, water heaters, range hoods, and bath fans remove conditioned air. The best solution is to build tight and ventilate right.